Changing conceptualizations of regression: What prospective studies reveal about the onset of autism spectrum disorder

The Association Between Children's Autism Spectrum Disorders and Central Nervous System Infections: Using a Nationwide Claims Database

Several studies have reported an association of autism spectrum disorder (ASD) with central nervous system (CNS) infections and intrauterine infections; however, the results remain unclear. This study aimed to examine this issue using an extensive national database. Utilizing JMDC medical claims database, we conducted a retrospective cohort study of children with at least three years of follow-up from birth, ensuring the mother's information was available. The focus was on the relationship between ASD incidence and exposures like viral meningitis/encephalitis, bacterial meningitis, and intrauterine infections. Cox proportional hazards was used to calculate hazard ratios (HRs) with covariates such as presence of maternal history of mental illness, preterm, low birth weight, respiratory and cardiac disorder, epilepsy, and cranial malformations. Sensitivity analysis was performed on sibling and multiple birth cohorts to adjust for genetic factors. Out of 276,195 mother-child pairs, bacterial meningitis was observed in 1326 (0.5%), viral meningitis/encephalitis in 6066 (2.2%), intrauterine infection in 3722 (1.3%), and ASD in 14,229 (5.2%) children. The adjusted HRs (95% confidence interval, p value) for ASD were 1.40 (1.25-1.57, p < 0.001), 1.14 (1.02-1.26, p = 0.013), and 1.06 (0.87-1.30, p = 0.539) for viral meningitis/encephalitis, intrauterine infection, and bacterial meningitis, respectively. After sensitivity analysis, the HRs for viral meningitis/encephalitis and ASD remained significantly high. Viral meningitis/encephalitis may be an independent risk factor for ASD. Awareness of this risk among healthcare professionals can lead to early intervention and potentially improved outcomes for affected children.

Sensory-movement underpinnings of lifelong neurodivergence: getting a grip on autism

While the autism diagnosis emphasizes "deficits" in social communication, the article advances that sensory-movement differences underpin autism through a review of the following sources of evidence. This account critically challenges "autistic regression", with evidence that sensory-movement features appear by birth as the earliest signs of autism and underlie the behavioral differences used for diagnosis, which may reflect adaptations to inherent differences and misunderstandings from others. Sensory and motor differences are salient to autistic people, but they often go underrecognized by others. They cause cascading effects in infancy on behavior and communication through differences in sensorimotor learning, automatic imitation, eye contact, sensory perception, and interests. The article then explains how sensory processing differences may influence reduced perceptual narrowing, which involves a bottom-up information processing style grounded in the surrounding environment. Furthermore, this bottom-up processing may grow from reduced sensory integration in feedback loops potentially involving the cerebellum of the brain. The article then moves into implications for the widespread consequences of these inherent differences on quality of life. The article closes with implications for autism as a construct (including underestimated empathy and pain), testing the theory, providing sensory-sensitive support and acceptance of autistic people, and applications to diverse autistic people. The theory may apply particularly well to autistic women and girls, autistic people with speech divergence, autistic people with ADHD, and autistic people with co-occurring sensory and motor-related neurodivergences. Throughout the article, the theory also provides clinical, neurological, and experiential evidence for sensory and motor differences as lifelong, challenging the notion of "losing" (an) autism (diagnosis) as instead reflecting (risky and not necessarily "successful") camouflaging.

Comparative Analysis of Phenotypic and Genotypic Differences Between Individuals Affected by Regressive and Non-Regressive Autism: A Cross-Sectional Study

Development among autistic youth varies widely. A subgroup of children experiences regression, defined as the loss of previously acquired developmental skills. Various genetic and environmental factors have been suggested as potential contributors. This study aimed to compare the developmental profiles of children and youth with regression to those without and identify factors associated with regression. Data from the Province of Ontario Neurodevelopmental Disorders (POND) Network was analyzed, including 930 eligible participants. Regression classification was based on the Autism Diagnostic Interview-Revised (ADI-R). Differences in demographic information, medical history, mental health, cognitive and adaptive functioning, and molecular genetic findings were examined between individuals with regressive and non-regressive autism. Among participants, 211 (22.7%) had regressive autism. Lower Full-Scale IQ (p corrected = 0.015) and adaptive function (ABAS-2) scores (p corrected = 0.015) were identified in the regressive group. No statistically significant differences in mental health outcomes (measured by the Child Behavior Checklist, CBCL) or socialization and core symptom severity (measured by the Social Communication Questionnaire, SCQ) were found. There were no notable differences in other factors hypothesized to contribute to regression, such as pregnancy duration, family history of autism, caregivers' education levels, or sleep disorders, except for a higher prevalence of epilepsy in the regressive group (p = 0.001). Rare and common genetic features of both groups are described. In conclusion, autistic youth with regression tend to have lower cognitive and adaptive scores and may experience higher epilepsy rates. Further powered studies are needed to explore the genomic architecture of autistic regression.

Investigation of Neuronal-Astroglial Injury Proteins and MMP-9 Serum Levels in Autism Spectrum Disorder and Their Relationship With Autistic Regression

OBJECTIVE

This study compared serum levels of S100B, GFAP, UCHL-1, NF-H and MMP-9 between children with Autism Spectrum Disorder (ASD) and controls, focusing on their association with regression in ASD. We hypothesized that neuroinflammation and neuronal/astroglial damage markers would be higher in the ASD group than in controls and even more elevated in the regressive ASD subgroup compared to the non-regressive subgroup.

METHODS

The study included 50 children with ASD (ages 4-10) and 30 healthy children. Participants underwent the K-SADS-PL diagnostic interview, CARS, a semi-structured interview for regression, ABC, AuBC, CPRS-RS and SRS assessments. Serum levels of S100B, GFAP, UCHL-1, NF-H and MMP-9 were measured using flow cytometry and ELISA.

RESULTS

Serum levels of S100B, GFAP, UCHL-1, NF-H and MMP-9 showed no significant differences between the ASD and control groups. Within the ASD group, no notable differences were found in sociodemographic, clinical characteristics, or serum marker levels between those with and without regression.

CONCLUSION

The findings obtained in this study suggested that it is necessary to question whether the peripheral circulation can represent changes in central nervous system and to review the existence of autistic regression as a separate entity in ASD in terms of clinical features and etiopathogenesis.

Pragmatic performance, its relationship with symptom severity, and early clinical predictors of pragmatics in 5 ~ 6-year-old children with autism spectrum disorder

BACKGROUND

Pragmatic language refers to using spoken language to convey messages effectively across diverse social communication contexts. However, minimal longitudinal research has focused on defining early predictors of pragmatic development in children with autism spectrum disorder (ASD).

METHODS

In the present study, 71 children with ASD and 38 age- and gender- matched 24- to 30-month-old typically developing (TD) children were enrolled. Social-communication, language, and parent‒child interaction measures were collected for the ASD group at baseline. Three years later, all subjects were assessed for pragmatic ability via the Chinese version of the Language Use Inventory (LUI-Mandarin). First, the differences in pragmatic performance between the ASD and TD groups at follow-up were analyzed. Second, pragmatic performance was correlated with autism symptomatology at follow-up, as well as the structural language difficulties and joint engagement (JE) levels at baseline in the ASD group. Furthermore, hierarchical multiple regression analyses and machine learning techniques were performed to explore the effects of early potential predictors of pragmatic development in the ASD group.

RESULTS

First, our results revealed that performance was significantly lower in the ASD than in the TD group with respect to the LUI-Mandarin total scores and subscale scores (except for subscale C). Second, correlation analysis revealed that more severe symptoms of ASD at follow-up were associated with lower LUI-Mandarin total scores and better language performance on the Gesell Developmental Schedules (GDS). Additionally, increased proportions of supported JE (SJE) states were associated with higher LUI-Mandarin total scores. In contrast, increased proportions of unengaged (UE) states were associated with lower LUI-Mandarin total scores in the ASD group. Third, hierarchical multiple regression analyses and machine learning techniques indicated that the proportions of SJE during parent‒child interactions, as well as the degree of social symptoms and structural language impairments, were significant contributors to pragmatic development for the ASD group in the prediction models.

CONCLUSION

In summary, our findings suggest that pragmatic language difficulties are present in children with ASD as early as preschool age. Additionally, given the close correlation between the LUI-Mandarin score and symptom severity on the ADOS/ADI-R, the LUI-Mandarin might be a good way to triage children who need to wait a long time for a more extensive evaluation. Furthermore, this study provides new insights into potential targets for pragmatic interventions, and interventions can be designed to promote SJE between caregivers and children in future work.

Deficiency of FABP7 Triggers Premature Neural Differentiation in Idiopathic Normocephalic Autism Organoids

Autism spectrum disorder (ASD), which is caused by heterogeneous genetic and environmental factors, is characterized by diverse clinical phenotypes linked to distinct pathological mechanisms. ASD individuals with a shared clinical phenotype might contribute to revealing the molecular mechanism underlying ASD progression. Here, it is generated induced pluripotent stem cell (iPSC)-derived cerebral organoids from normocephalic individuals with ASD in a prospective birth cohort with a shared clinical diagnosis. Multiple cell lines and time series scRNA-seq combined with a histomorphological analysis revealed premature neural differentiation of neural stem cells (NSCs) and decreased expression of Fatty acid binding protein 7 (FABP7) in ASD organoids. It is subsequently revealed alterations in the phosphorylation levels of Mitogen-Activated Protein Kinase Kinase 1/2 (MEK1/2), which are downstream of FABP7, and the regulation of the FABP7/MEK pathway reversed improper neural differentiation in the ASD organoids. Moreover, both Fabp7-knockdown and MEK2-overexpressing mice exhibited repetitive stereotyped behaviors and social defects relevant to autism. This study reveals the role of the FABP7/MEK pathway in abnormal NSC differentiation in normocephalic individuals with ASD, which might provide a promising therapeutic target for ASD treatment.

Pupillary responses for social versus non-social stimuli in autism: A systematic review and meta-analysis

Pupillometry has gained attention as a valuable tool for assessing autonomic nervous system activity and studying phasic changes in pupil size to comprehend underlying neurocognitive mechanisms. However, knowledge regarding pupillary responses to social processing in autism is limited. We conducted a systematic review and meta-analysis, examining research studies on pupil size changes that compare social and non-social stimuli in autism. Electronic searches were performed for articles up to September 2023 and relevant studies were evaluated following PRISMA guidelines. Out of 284 articles screened, 14 studies were eligible for systematic review. The results indicated that non-autistic individuals showed larger pupil size for social compared to non-social stimuli (g = 0.54; 95 % CI [0.25, 0.82]), whereas autistic individuals seemed to exhibit no differences between the two conditions. However, high heterogeneity was observed between studies in autistic populations, compromising interpretability. Despite such limitations, pupillary responses may constitute an objective physiological marker of social processing in autism. This review emphasizes the need for further investigations into pupillary responses in autism across different life stages.

Early gesture development as a predictor of autism spectrum disorder in elevated-likelihood infants of ASD

BACKGROUND

Gesture difficulties have been reported in later-born siblings of children with autism spectrum disorder (ASD). Careful observation of gesture development during the first two years of children at elevated likelihood (EL) of developing ASD may identify behavioral indicators that facilitate early diagnosis.

METHODS

This study enrolled 47 EL infants and 27 low-likelihood (LL) infants to explore gesture developmental trajectories and the predictive value of gesture to expedite the early detection of core characteristics of ASD. Gesture frequency, communication function, and integration ability were observed and coded from a semi-structured assessment administered longitudinally across 9-19 months of age. We conducted the Autism Diagnostic Observation Schedule assessment at 18-19 months for ASD's core characteristics.

RESULTS

The development of joint attention (JA) gestures was slower in the EL than in the LL group. The trajectories of the two groups began to diverge at 14-18 months. Children who reached the diagnostic cutoff point for ASD showed reductions in social interaction gestures at 12-13 months, in gestures integrated with any two communication skills (G-M) at 15-16 months; and in gestures integrated with eye contact (G-E) at 18-19 months. Overall gesture and G-M integration were associated with an overall ADOS communication and social interaction score.

CONCLUSIONS

The developmental trajectories of JA gestures of EL and LL children differed. G-M gestures represent early indicators that may be a predictor of ASD.

Exploration of Risk Factors for Language Regression According to Parent Reports in Turkish Children with Autism Spectrum Disorder

Background

Approximately 30% of autism spectrum disorder (ASD) cases exhibit developmental regression after a period of typical development, leading to what is known as regressive autism. Our understanding of the factors underlying regression, including precise mechanisms, clinical features, and risk factors, remains limited. This study aims to compare children with ASD with language regression (ASD-LR) to those without developmental regression (ASD-NR) in terms of clinical and demographic characteristics and to identify potential predictors.

Methods

In this cross-sectional retrospective study, children aged 2-6 diagnosed with ASD-LR were matched for age and gender with children diagnosed with ASD-NR between January 2023 and January 2024. The groups were compared in terms of demographic and clinical characteristics.

Results

The mean age of the ASD-LR group (n = 32) was 52.16 ± 14.56 months, and the ASD-NR group (n = 50) had a mean age of 48.76 ± 13.41 months. Univariate analyses revealed no significant differences in autism severity between groups in clinician (P = .367) and parent evaluations (P = .541). However, in the ASD-LR group, a significant relationship was found between regression, a history of febrile seizures (P = .012), a father's psychiatric background (P = .002), and a family history of psychiatric disorders (P < .001). Family history of psychiatric disorders (OR 7.54, 95% CI 1.10-51.64, P = .040) and cesarean delivery (odds ratio 3.90, 95% CI 1.05-14.47, P = .042) were identified as independent predictors of language regression.

Conclusion

The results indicate that regression may be associated with both genetic and environmental factors, including a family history of psychiatric disorders, cesarean delivery, and febrile seizure. Future research should focus on explaining these factors and identifying potential preventive measures.

Reciprocal Associations Between Language Ability and Social Functioning Development in Pre-verbal Autistic Children

Longitudinal research on language abilities and social functioning in young children suggests that gains in one domain affect gains in the other. However, few studies have examined inter-relations of language and social functioning jointly among young children diagnosed with autism spectrum disorder (ASD). Pre-verbal toddlers with ASD are a group of particular clinical relevance, given that greater language abilities at school entry have been associated with positive long-term adjustment in many areas, including adaptive and social functioning. Reduced attention to and engagement in social interactions among autistic toddlers who are not yet speaking may interfere with language development concurrently and over time. The present study examined reciprocal associations between language ability and social functioning over a 2-year period across three time points in a sample of 90 pre-verbal autistic toddlers using cross-lagged panel analyses conducted in MPlus. Cross-lagged panel analyses revealed significant within-timepoint synchronous correlations, within-domain autoregressive paths over time, and as hypothesized, reciprocal significance in all cross-lagged paths. For very young pre-verbal children with ASD, language ability and social functioning appear to exert concurrent and cascading developmental influences on one another. Targeting both language and social functioning simultaneously may enhance intervention efficacy for very young pre-verbal children with ASD.

Attainment and loss of early social-communication skills across neurodevelopmental conditions in the Norwegian Mother, Father and Child Cohort Study

BACKGROUND

Delays and loss of early-emerging social-communication skills are often discussed as unique to autism. However, most studies of regression have relied on retrospective recall and clinical samples. Here, we examine attainment and loss of social-communication skills in the population-based Norwegian Mother, Father and Child Cohort Study (MoBa).

METHODS

Mothers rated their child's attainment of 10 early-emerging social-communication skills at ages 18 and 36 months (N = 40,613, 50.9% male). Prospectively reported loss was defined as skill presence at 18 months but absence at 36 months. At 36 months, mothers also recalled whether the child had lost social-communication skills. The Norwegian Patient Registry was used to capture diagnoses of Autism Spectrum Disorder (autism) and other neurodevelopmental disabilities (NDDs).

RESULTS

Delay in at least one skill was observed in 14% of the sample and loss in 5.4%. Recalled loss of social-communication skills was rare (0.86%) and showed low convergence with prospectively reported loss. Delay and especially loss were associated with elevated odds of an autism diagnosis (n = 383) versus no autism diagnosis (n = 40,230; ≥3 skills delayed: OR = 7.09[4.15,12.11]; ≥3 skills lost: OR = 30.66[17.30,54.33]). They were also associated with an increased likelihood of autism compared to some other NDDs. Delay (relative risk [RR] = 4.16[2.08, 8.33]) and loss (RR = 10.00[3.70, 25.00]) associated with increased likelihood of autism versus ADHD, and loss (RR = 4.35[1.28,14.29]), but not delay (RR = 2.00[0.78,5.26]), associated with increased likelihood of autism compared to language disability. Conversely, delay conferred decreased likelihood of autism versus intellectual disability (RR = 0.11[0.06,0.21]), and loss was not reliably associated with likelihood of autism versus intellectual disability (RR = 1.89[0.44,8.33]).

CONCLUSIONS

This population-based study suggests that loss of early social communication skills is more common than studies using retrospective reports have indicated and is observed across several NDD diagnoses (not just autism). Nevertheless, most children with NDD diagnoses showed no reported delay or loss in these prospectively measured skills.

Multidimensional Analysis of a Social Behavior Identifies Regression and Phenotypic Heterogeneity in a Female Mouse Model for Rett Syndrome

Regression is a key feature of neurodevelopmental disorders such as autism spectrum disorder, Fragile X syndrome, and Rett syndrome (RTT). RTT is caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). It is characterized by an early period of typical development with subsequent regression of previously acquired motor and speech skills in girls. The syndromic phenotypes are individualistic and dynamic over time. Thus far, it has been difficult to capture these dynamics and syndromic heterogeneity in the preclinical Mecp2-heterozygous female mouse model (Het). The emergence of computational neuroethology tools allows for robust analysis of complex and dynamic behaviors to model endophenotypes in preclinical models. Toward this first step, we utilized DeepLabCut, a marker-less pose estimation software to quantify trajectory kinematics and multidimensional analysis to characterize behavioral heterogeneity in Het in the previously benchmarked, ethologically relevant social cognition task of pup retrieval. We report the identification of two distinct phenotypes of adult Het: Het that display a delay in efficiency in early days and then improve over days like wild-type mice and Het that regress and perform worse in later days. Furthermore, regression is dependent on age and behavioral context and can be detected in the initial days of retrieval. Together, the novel identification of two populations of Het suggests differential effects on neural circuitry, opens new avenues to investigate the underlying molecular and cellular mechanisms of heterogeneity, and designs better studies for stratifying therapeutics.

Pragmatic competence in people with dual diagnosis: down syndrome and autism spectrum disorder

BACKGROUND

Pragmatics is an area that can be affected in a wide variety of disorders. In this sense, Syndromic Autism is defined as a disorder in which a causal link is established between an associated syndrome and Autism Spectrum Disorder (ASD). Likewise, Down Syndrome (DS) is one of the main genetically based syndromes in which ASD is described as one of its possible manifestations. In this direction, people with DS are described as social beings whereas in ASD there seems to be a specific alteration of this domain.

METHODS

In this study, pragmatic performance was analysed in a sample of 72 participants, where comparisons were made between the scores obtained by children with ASD (n = 24), with DS (n = 24) and with DS + ASD (n = 24).

RESULTS

The Social Communication Questionnaire (SCQ), the Block Objective and Criterial Language Battery (BLOC-SR) and the Neuropsychology subtest (NEPSY-II) aimed at Theory of Mind (ToM) identified significant differences between the groups. However, two-to-two comparisons reported no significant differences between DS and DS + ASD.

CONCLUSIONS

Although several studies report differences between the three proposed groups, our data seem to suggest that ASD symptomatology in DS is associated with Intellectual Developmental Disorder (IDD). However, the lack of solid scientific evidence regarding comorbid diagnosis makes further research along these lines indispensable.

TRIAL REGISTRATION

This study was approved by the Ethics Committee for Social Research at UCLM with reference CEIS-704,511-L8M4.

Using the Griffiths Mental Development Scales to Evaluate a Developmental Profile of Children with Autism Spectrum Disorder and Their Symptomatologic Severity

Early diagnosis is crucial for Autism spectrum disorder (ASD) and is achieved through a screening of developmental indicators to recognise children who are at risk of autism. One of the most widely used instruments in clinical practice for assessing child development is the Griffiths Mental Development Scale (GMDS). We sought (a) to assess longitudinally whether children diagnosed with ASD, with a mean age of 33.50 months (SD 7.69 months), show a developmental delay of abilities measured by the GMDS over time and (b) to analyse which skills of the GMDS could be associate to the symptomatologic severity of ASD. Our results showed lower scores of General Quotient and all sub-quotients of GMDS from first (T0) to second assessment (T1), except for the Performance sub-quotient. Three sub-quotients (Personal-Social, Hearing and Language and Practical Reasoning) also associate symptom severity at the time when the diagnosis of ASD is made.

Disease Course and Response to Immunotherapy in Children With Childhood Disintegrative Disorder: A Retrospective Case Series

Childhood disintegrative disorder is a poorly understood neurobehavioral disorder of early childhood characterized by acute to subacute profound regression in previously developed language, social behavior, and adaptive functions. The etiology of childhood disintegrative disorder remains unknown and treatment is focused on symptomatic management. Interest in neuroinflammatory mechanisms has grown with the increased recognition of autoimmune brain diseases and similarities between the presenting symptoms of childhood disintegrative disorder and pediatric autoimmune encephalitis. Importantly, a diagnosis of pediatric autoimmune encephalitis requires evidence of inflammation on paraclinical testing, which is absent in childhood disintegrative disorder. Here we report 5 children with childhood disintegrative disorder who were initially diagnosed with possible autoimmune encephalitis and treated with immunotherapy. Two children had provocative improvements, whereas 3 did not change significantly on immunotherapy. Additionally, a sixth patient with childhood disintegrative disorder evaluated in our Autoimmune Brain Disease Clinic showed spontaneous improvement and is included to highlight the variable natural history of childhood disintegrative disorder that may mimic treatment responsiveness.

Developmental regression in children: Current and future directions

Developmental regression describes when a child loses previously established skills, such as the ability to speak words and is most recognised in neurodevelopmental conditions including Autism; Developmental Epileptic Encephalopathies, such as Landau Kleffner syndrome, and genetic conditions such as Rett syndrome and Phelan McDermid syndrome. Although studies have reported developmental regression for over 100 years, there remain significant knowledge gaps within and between conditions that feature developmental regression. The certainty of evidence from earlier work has been limited by condition-specific studies, retrospective methodology, and inconsistency in the definitions and measures used for classification. Given prior limitations in the field, there is a paucity of knowledge about neurocognitive mechanisms, trajectories and outcomes for children with developmental regression, and their families. Here we provide a comprehensive overview, synthesise key definitions, clinical measures, and aetiological clues associated with developmental regression and discuss impacts on caregiver physical and mental health to clarify challenges and highlight future directions in the field.

Impaired white matter integrity in infants and young children with autism spectrum disorder: What evidence does diffusion tensor imaging provide?

BACKGROUND

Abnormal functional connections are associated with impaired white matter tract integrity in the brain. Diffusion tensor imaging (DTI) is a promising method for evaluating white matter integrity in infants and young children. This work aims to shed light on the location and nature of the decrease in white matter integrity.

METHODS

Here, the results of 19 studies have been presented that investigated white matter integrity in infants and young children (6 months to 12 years) with autism using diffusion tensor imaging.

RESULTS

In most of the reviewed studies, an increase in Fractional Anisotropy (FA) and a decrease in Radial Diffusivity (RD) were reported in Corpus Callosum (CC), Uncinate Fasciculus (UF), Cingulum (Cg), Inferior Longitudinal Fasciculus (ILF), and Superior Longitudinal Fasciculus (SLF), and in the Inferior Fronto-Occipital Fasciculus (IFOF) tract, a decrease in FA and an increase in RD were reported.

CONCLUSION

In the reviewed articles, except for one study, the diffusion indices were different compared to the control group.

The Role of SNAP-25 in Autism Spectrum Disorders Onset Patterns

Autism spectrum disorders (ASD) can present with different onset and timing of symptom development; children may manifest symptoms early in their first year of life, i.e., early onset (EO-ASD), or may lose already achieved skills during their second year of life, thus showing a regressive-type onset (RO-ASD). It is still controversial whether regression represents a neurobiological subtype of ASD, resulting from distinct genetic and environmental causes. We focused this study on the 25 kD synaptosomal-associated protein (SNAP-25) gene involved in both post-synaptic formation and adhesion and considered a key player in the pathogenesis of ASD. To this end, four single nucleotide polymorphisms (SNPs) of the SNAP-25 gene, rs363050, rs363039, rs363043, and rs1051312, already known to be involved in neurodevelopmental and psychiatric disorders, were analyzed in a cohort of 69 children with EO-ASD and 58 children with RO-ASD. Both the rs363039 G allele and GG genotype were significantly more frequently carried by patients with EO-ASD than those with RO-ASD and healthy controls (HC). On the contrary, the rs1051312 T allele and TT genotype were more frequent in individuals with RO-ASD than those with EO-ASD and HC. Thus, two different SNAP-25 alleles/genotypes seem to discriminate between EO-ASD and RO-ASD. Notably, rs1051312 is located in the 3' untranslated region (UTR) of the gene and is the target of microRNA (miRNA) regulation, suggesting a possible epigenetic role in the onset of regressive autism. These SNPs, by discriminating two different onset patterns, may represent diagnostic biomarkers of ASD and may provide insight into the different biological mechanisms towards the development of better tailored therapeutic and rehabilitative approaches.

Risk factors and clinical characteristics of autism spectrum disorder with regression in China

Autism spectrum disorder with regression (ASD-R) is characterized by the loss of previously acquired skills during the initial year of life. This study aimed to investigate the clinical characteristics, patterns of regression, and potential risk factors associated with ASD-R in the Chinese Han population. A case-control study was conducted between September 2020 and March 2022. A total of 186 children were enrolled, including 58 children with ASD-R, 70 with ASD without regression (ASD-NR), and 58 typically developing children. Demographic information, clinical characteristics, and potential risk factors related to ASD-R were assessed using a combination of questionnaires, interviews, and physician assessments. The results revealed that children with ASD-R exhibited more severe impairments in social communication and stereotyped behaviors compared with those with ASD-NR. Language regression, constituting 40% of cases within the ASD-R group, was found to be the most common type of regression. Furthermore, our analysis revealed that fever (OR = 4.01, 95% CI: 1.26-12.76) and diarrhea (OR = 6.32, 95% CI: 1.38-29.03) were identified as significant risk factors for ASD-R. These findings contribute to our understanding of the heterogeneity of ASD and highlight the importance of considering immune responses and gastrointestinal factors in the etiology of ASD-R.

Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study

Since its introduction, aspartame-the leading sweetener in U.S. diet sodas (DS)-has been reported to cause neurological problems in some users. In prospective studies, the offspring of mothers who consumed diet sodas/beverages (DSB) daily during pregnancy experienced increased health problems. We hypothesized that gestational/early-life exposure to ≥1 DS/day (DSearly) or equivalent aspartame (ASPearly: ≥177 mg/day) increases autism risk. The case-control Autism Tooth Fairy Study obtained retrospective dietary recalls for DSB and aspartame consumption during pregnancy/breastfeeding from the mothers of 235 offspring with autism spectrum disorder (ASD: cases) and 121 neurotypically developing offspring (controls). The exposure odds ratios (ORs) for DSearly and ASPearly were computed for autism, ASD, and the non-regressive conditions of each. Among males, the DSearly odds were tripled for autism (OR = 3.1; 95% CI: 1.02, 9.7) and non-regressive autism (OR = 3.5; 95% CI: 1.1, 11.1); the ASPearly odds were even higher: OR = 3.4 (95% CI: 1.1, 10.4) and 3.7 (95% CI: 1.2, 11.8), respectively (p < 0.05 for each). The ORs for non-regressive ASD in males were almost tripled but were not statistically significant: DSearly OR = 2.7 (95% CI: 0.9, 8.4); ASPearly OR = 2.9 (95% CI: 0.9, 8.8). No statistically significant associations were found in females. Our findings contribute to the growing literature raising concerns about potential offspring harm from maternal DSB/aspartame intake in pregnancy.

Prototypical autism: New diagnostic criteria and asymmetrical bifurcation model

The current "autism spectrum" DSM 5 diagnostic criteria and autism standardized diagnostic instruments promote considerable heterogeneity or clinical indecision and may be detrimental to the advancement of fundamental research on autism mechanisms. To increase clinical specificity and reorient research towards core autistic presentations, we propose new diagnostic criteria for prototypical autism during the age of 2- to 5-years. We include autism within other non-dominant, familiarly aggregated phenomena sharing asymmetrical developmental bifurcations, such as twin pregnancy, left handedness, and breech presentation/delivery. Following this model, nature, trajectory, and positive/negative signs structure of autism would result from the polarized problem of whether or not language and information is processed in a socially biased manner. Prototypical autism would follow a canonical developmental trajectory by which a gradual decline in social bias in the processing of incoming information, overtly beginning at the end of the first year, bifurcates into a prototypical autistic presentation in the second half of the second year of life. This bifurcation event is followed by a plateau, in which these atypicalities show maximal stringency and distinctiveness, and then ultimately, in most cases, by partial normalization. During the plateau period, the orientation towards, and processing of, information is considerably modified, with an absence of bias for social information, contrasting with a high level of interest in complex, unbiased information, independently of its social or non-social nature. Integrating autism into asymmetrical developmental bifurcations would explain the absence of deleterious neurological and genetic markers and the presence of familial transmission in canonical autistic presentations.

Epigenomic signatures reveal mechanistic clues and predictive markers for autism spectrum disorder

Autism spectrum disorder (ASD) comprises a heterogeneous group of neurodevelopmental outcomes in children with a commonality in deficits in social communication and language combined with repetitive behaviors and interests. The etiology of ASD is heterogeneous, as several hundred genes have been implicated as well as multiple in utero environmental exposures. Over the past two decades, epigenetic investigations, including DNA methylation, have emerged as a novel way to capture the complex interface of multivariate ASD etiologies. More recently, epigenome-wide association studies using human brain and surrogate accessible tissues have revealed some convergent genes that are epigenetically altered in ASD, many of which overlap with known genetic risk factors. Unlike transcriptomes, epigenomic signatures defined by DNA methylation from surrogate tissues such as placenta and cord blood can reflect past differences in fetal brain gene transcription, transcription factor binding, and chromatin. For example, the discovery of NHIP (neuronal hypoxia inducible, placenta associated) through an epigenome-wide association in placenta, identified a common genetic risk for ASD that was modified by prenatal vitamin use. While epigenomic signatures are distinct between different genetic syndromic causes of ASD, bivalent chromatin and some convergent gene pathways are consistently epigenetically altered in both syndromic and idiopathic ASD, as well as some environmental exposures. Together, these epigenomic signatures hold promising clues towards improved early prediction and prevention of ASD as well genes and gene pathways to target for pharmacological interventions. Future advancements in single cell and multi-omic technologies, machine learning, as well as non-invasive screening of epigenomic signatures during pregnancy or newborn periods are expected to continue to impact the translatability of the recent discoveries in epigenomics to precision public health.

Common developmental trajectories and clinical identification of children with fetal alcohol spectrum disorders: A synthesis of the literature

At an estimated prevalence of up to five percent in the general population, fetal alcohol spectrum disorders (FASD) are the most common neurodevelopmental disorder, at least if not more prevalent than autism (2.3%). Despite this prevalence in the general population, pediatricians and other developmental specialists have thus far failed to diagnose this disability, leaving most children and adults without the supports provided for most other disabilities. This paper will provide a review of clinically relevant literature that describes the developmental challenges of children with fetal alcohol spectrum disorders and addresses similarities to and differences of FASD from other neurodevelopmental disorders such as autism and attention deficit hyperactivity disorder. A subsequent discussion will describe how a diagnosis of an FASD can establish a basis for understanding the developmental and behavioral challenges of children with an FASD, and how specific interventions can help support child development and maximize adult independence.

Latent class analysis to characterize neonatal risk for neurodevelopmental differences

BACKGROUND

Neonatal risk factors, such as preterm birth and low birth weight, have been robustly linked to neurodevelopmental deficits, yet it is still unclear why some infants born preterm and/or low birth weight experience neurodevelopmental difficulties while others do not. The current study investigated this heterogeneity in neurodevelopmental abilities by examining additional neonatal morbidities as risk factors, utilizing latent class analysis to classify neonates into groups based on similar neonatal risk factors, and including neonates from the full spectrum of gestational age.

METHODS

Neonates who received neonatal care at an academic public hospital during an almost 10-year period (n = 19,951) were included in the latent class analysis, and 21 neonatal indicators of health were used. Neonatal class, sex, and the interaction between neonatal class and sex were used to examine differences in neurodevelopment at 18 months of age in a typically developing population.

RESULTS

The best fitting model included five infant classes: healthy, hypoxic, critically ill, minorly ill, and complicated delivery. Scores on the parent-rated neurodevelopmental measure differed by class such that infants in the critically ill, minorly ill, and complicated delivery classes had lower scores. There was no main effect of sex on the neurodevelopmental measure scores, but the interaction between sex and neonatal class was significant for three out of five neurodevelopmental domains.

CONCLUSIONS

The current study extends the understanding of risk factors in neurodevelopment by including several neonatal medical conditions that are often overlooked and by using a person-centered, as opposed to variable-centered, approach. Future work should continue to examine risk factors, such as maternal health during pregnancy and medical interventions for newborns, in relation to neonatal risks and neurodevelopment by using a person-centered approach.

Using developmental regression to reorganize the clinical importance of autistic atypicalities

Early regression (ER) is often reported in autistic children with a prototypical phenotype and has been proposed as a possible pathognomonic sign present in most autistic children. Despite the uncertainties attached to its definition and report, using ER to anchor the autism phenotype could help identify the signs that best contribute to an autism diagnosis. We extracted retrospective data from 1547 autistic children between the ages of 6 and 18 years from the Simons Simplex collection. Logistic regression identified the atypicalities associated with a history of ER. Stepwise variable selection using logistic regression analysis followed by a bootstrap procedure of 1000 iterations identified the cluster of atypicalities best associated with ER. Linear and logistic regressions measured the association between combinations of atypicalities within the identified cluster and adaptative behaviors, diagnostic areas of severity, and other categories. Seven atypicalities significantly increased the likelihood of having experienced ER (OR = 1.73-2.13). Four ("hand leading-ever", "pronominal reversal-ever", "never shakes head at age 4-5" and "stereotypic use of objects or interest in parts of objects-ever"), when grouped together, best characterized the phenotype of verbal autistic children with ER. This clustering of signs was associated with certain persistent language difficulties, higher summary scores on a diagnostic scale for autism, and greater odds of receiving an "autistic disorder" diagnosis instead of another pervasive developmental disorder (PDD) diagnosis. These results raise questions about using language as a clinical specifier, defining cross-sectional signs independent of their relationship with an early developmental trajectory, and relying on polythetic criteria or equivalent weighted autistic atypicalities.

Emerging signs of autism spectrum disorder in infancy: Putative neural substrate

Autism spectrum disorder (ASD) is characterized by altered development of the social brain with prominent atypical features in the fronto-temporo-parietal cortex and cerebellum. Early signs of ASD emerge between 6 and 12 months: reduced social communication, slightly less advanced motor development, and repetitive behaviour. The fronto-temporo-parietal cortex and cerebellum play a prominent role in the development of social communication, whereas fronto-parietal-cerebellar networks are involved in the planning of movements, that is, movement selection. Atypical sensory responsivity, a core feature of ASD, may result in impaired development of social communication and motor skills and/or selection of atypical repetitive behaviour. In the first postnatal year, the brain areas involved are characterized by gradual dissolution of temporary structures: the fronto-temporo-parietal cortical subplate and cerebellar external granular layer. It is hypothesized that altered dissolution of the transient structures opens the window for the expression of early signs of ASD arising in the impaired developing permanent networks. WHAT THIS PAPER ADDS: The early social and motor signs of autism spectrum disorder emerge between the ages of 6 and 12 months. Altered dissolution of transient brain structures in the fronto-temporo-parietal cortex and cerebellum may underlie the emergence of these early signs.

Predictors of language regression and its association with subsequent communication development in children with autism

BACKGROUND

Language regression, broadly defined as the loss of acquired language skills in early childhood, is a distinctive feature of autism. Little is known about the factors underlying regression or the prognosis of children who exhibit regression. We examine potential predictors of language regression and test its association with language development in a prospective longitudinal sample of children with autism spectrum disorder (ASD) from diagnosis to age 10 years.

METHODS

We analysed data from Pathways in ASD, a prospective longitudinal study of 421 children enrolled around the time of an autism diagnosis between 2 and 5 years. Autism Diagnostic Interview-Revised data were available for 408 children, of whom 90 (22%) were classified as having language regression.

RESULTS

Demographic and other health factors including caregiver education, family income, child sex, reported seizures, and age of enrolment did not differ between children with and without language regression. Children with language regression walked earlier and attained first words sooner than those without regression. However, both groups attained phrase speech at comparable ages. Those with regression exhibited greater delays in expressive and receptive communication over the follow-up period, although this effect was attenuated when accounting for baseline differences in motor and cognitive ability. Overall, those with language regression continued to exhibit expressive but not receptive communication delay compared to those without regression. Communication trajectories were heterogeneous to age 10 years, irrespective of regression status.

CONCLUSIONS

Although language regression can be alarming, our findings confirm that its occurrence does not necessarily foreshadow worse developmental outcomes relative to those without regression. Although a discrepancy in age-equivalent communication skills may persist, this can be expected to be of less practical importance with rising average levels of skills. Future studies need to account for the significant variability in language trajectories by considering factors beyond developmental regression.

Description of Clinician-Diagnosed Regression at Time of Autism Spectrum Disorder Diagnosis in Toddlers

OBJECTIVE

Previous studies have reported varying rates of regression in children with autism spectrum disorder (ASD). We sought to (1) determine the rate of clinician-diagnosed regression for young children with ASD and (2) compare developmental functioning and ASD symptoms of children with versus without regression.

METHODS

We conducted a retrospective chart review of toddlers (age 18-36 months) with Diagnostic and Statistical Manual-5 ASD. We abstracted cognitive, language, adaptive, and motor functioning standard scores and ASD core symptoms. Regression was defined as "clinician-diagnosed regression accompanied by recommendation for a medical workup." We used propensity scores to match each participant with regression (n = 20) one-to-one with a participant without regression (n = 20). We compared the groups on developmental scores using independent sample t tests and on core ASD symptoms using Pearson's χ 2 test.

RESULTS

Of the 500 children with ASD, n = 20 (4%) had regression (defined above). Children with regression had lower Bayley cognitive and language scores and lower Vineland adaptive scores compared with those without regression (cognitive: 78.0 vs 85.5, p < 0.05; language: 56.9 vs 68.2, p < 0.01; adaptive: 70.0 vs 80.3; p < 0.01). There was no difference in motor scores across groups. There were no significant differences in the frequency of exhibiting core ASD symptoms for those with versus without regression.

CONCLUSION

In this clinical sample of children with ASD, regression was diagnosed in a small percentage (4%). Those with regression had lower cognitive, language, and adaptive skills compared with those without regression. Rates of clinician-diagnosed regression referred for medical workup are significantly lower than prior estimates based on parent report.

Early signs of autism in infants whose mothers suffered from a threatened preterm labour: a 30-month prospective follow-up study

Infants born after a threatened preterm labour (TPL infants) are at high risk of autism spectrum disorder (ASD). Studying this population may provide insight on the pathophysiological underpinnings of this condition. This study aimed to (i) ascertain the presence and autistic symptom load in TPL infants aged age 30 months relative to non-TPL infants, regardless of preterm birth; (ii) explore the association between early (at 6 months) psychomotor development and temperament features with the autistic symptom load of TPL infants at age 30 months and (iii) examine the association among perinatal risk factors for ASD development with the autistic symptom load of TPL infants at age 30 months. A group of 111 mother-infant pairs recruited at TPL diagnosis and a group of 47 healthy mother-infant controls completed the follow-up. Irrespective of preterm birth, TPL infants showed higher autistic symptom load at age 30 months than non-TPL infants. TPL infants presented poorer communication and problem-solving skills, reduced smiling and laughter, and greater vocal reactivity at age 6 months, predicting higher autistic symptom load at age 30 months. Higher levels of anxiety symptoms in TPL mothers after a TPL diagnosis also predicted higher autistic symptom load for the infants at age 30 months. These results suggest that TPL infants may be an undescribed cluster, with features that differentiate them from other "at-risk" populations. These findings support the need for routine assessment of TPL infants and screening of anxiety symptoms in mothers.

The “Primitive Brain Dysfunction” Theory of Autism: The Superior Colliculus Role

A better understanding of the pathogenesis of autism will help clarify our conception of the complexity of normal brain development. The crucial deficit may lie in the postnatal changes that vision produces in the brainstem nuclei during early life. The superior colliculus is the primary brainstem visual center. Although difficult to examine in humans with present techniques, it is known to support behaviors essential for every vertebrate to survive, such as the ability to pay attention to relevant stimuli and to produce automatic motor responses based on sensory input. From birth to death, it acts as a brain sentinel that influences basic aspects of our behavior. It is the main brainstem hub that lies between the environment and the rest of the higher neural system, making continuous, implicit decisions about where to direct our attention. The conserved cortex-like organization of the superior colliculus in all vertebrates allows the early appearance of primitive emotionally-related behaviors essential for survival. It contains first-line specialized neurons enabling the detection and tracking of faces and movements from birth. During development, it also sends the appropriate impulses to help shape brain areas necessary for social-communicative abilities. These abilities require the analysis of numerous variables, such as the simultaneous evaluation of incoming information sustained by separate brain networks (visual, auditory and sensory-motor, social, emotional, etc.), and predictive capabilities which compare present events to previous experiences and possible responses. These critical aspects of decision-making allow us to evaluate the impact that our response or behavior may provoke in others. The purpose of this review is to show that several enigmas about the complexity of autism might be explained by disruptions of collicular and brainstem functions. The results of two separate lines of investigation: 1. the cognitive, etiologic, and pathogenic aspects of autism on one hand, and two. the functional anatomy of the colliculus on the other, are considered in order to bridge the gap between basic brain science and clinical studies and to promote future research in this unexplored area.

Children with ASD and Communication Regression: Examining Pre-Loss Skills and Later Language Outcomes Through the Preschool Years

This study investigated receptive and expressive language outcomes in children with autism spectrum disorder (ASD) with and without a history of language/communication regression, employing three progressively less stringent definitions of regression. Data were derived from a large, longitudinal sample of children with ASD in which regression was assessed at approximately 30 months. Results indicated poorer receptive language and larger discrepancies between receptive and expressive language in the regression group than the group without regression at 44 months but not 66 months. Number of words used before loss predicted receptive language at 44 months. Overall, results suggest that a regression profile in ASD is associated with modest and transient impacts on language outcomes that are no longer discernable at school entry.

Identification of neurodevelopmental transition patterns from infancy to early childhood and risk factors predicting descending transition

It is unclear whether neurodevelopmental progress from infancy to early childhood remains stable. Moreover, little is known about the risk factors, if any, affecting neurodevelopmental descending transition patterns and the relationship between these patterns and later childhood adaptive behaviours. We used data of 875 children from the Hamamatsu Birth Cohort Study in Japan. Children’s neurodevelopment at 18 and 32 months and adaptive behaviours at 40 months were evaluated. Perinatal factors and infant overweight status at 18 months were investigated to identify descending-transition-associated risk factors. In the latent transition analysis, ultimately, three classes were identified for each time-point, resulting in nine transition patterns; among them, 10.4% of children showed descending class shifts (normal to delayed class). Such decelerated growth was predicted by maternal pre-pregnancy overweight status (odds ratio [OR] 2.49; 95% confidence interval [CI] 1.23, 5.02), low maternal educational history (OR 1.20; 95% CI 1.04, 1.36), and infant overweight status at 18 months (OR 5.89; 95% CI 1.26, 27.45). Children with descending transition showed poor functioning in adaptive behaviours at the age of 40 months. To prevent subsequent poor adaptive functioning, it may be necessary to consider that a certain percentage of children show decelerated growth.

Childhood infections and autism spectrum disorders and/or intellectual disability: a register-based cohort study

Objective

To explore the associations between childhood infections and subsequent diagnoses of autism spectrum disorder (ASD), intellectual disability (ID), and their co-occurrence.

Methods

The association between specialized care for any infection, defined by ICD-codes, and later ASD or ID was investigated in a register-based cohort of 556,732 individuals born 1987–2010, resident in Stockholm County, followed from birth to their 18th birthday or December 31, 2016. We considered as potential confounders children’s characteristics, family socioeconomic factors, obstetric complications, and parental histories of treatment for infection and psychiatric disorders in survival analyses with extended Cox regression models. Residual confounding by shared familial factors was addressed in sibling analyses using within-strata estimation in Cox regression models. Sensitivity analyses with the exclusion of congenital causes of ASD/ID and documented risk for infections were also performed.

Results

Crude estimates indicated that infections during childhood were associated with later ASD and ID with the largest risks observed for diagnoses involving ID. Inclusion of covariates, exclusion of congenital causes of ASD/ID from the population, and sibling comparisons highlighted the potential for confounding by both heritable and non-heritable factors, though risks remained in all adjusted models. In adjusted sibling comparisons, excluding congenital causes, infections were associated with later “ASD without ID” (HR 1.24, 95%CI 1.15–1.33), “ASD with ID” (1.57, 1.35–1.82), and “ID without ASD” (2.01, 1.76–2.28). Risks associated with infections varied by age at exposure and by age at diagnosis of ASD/ID.

Conclusions

Infections during childhood may contribute to a later diagnosis of ID and ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09422-4.

Regressive Autism Spectrum Disorder: High Levels of Total Secreted Amyloid Precursor Protein and Secreted Amyloid Precursor Protein-α in Plasma

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by social communication difficulties, repetitive behaviors, and parochial interests. Individuals with regressive ASD (RA), a unique subtype, have poor outcomes. Moreover, there are currently no validated blood-based biomarkers for ASD, hindering early diagnosis and treatment. This study was the first to examine plasma levels of total secreted amyloid precursor protein (sAPPtotal), secreted amyloid precursor protein-α (sAPPα), and secreted amyloid precursor protein-β (sAPPβ) in children diagnosed with RA (n = 23) and compare them with the levels in age-matched children with non-regressive ASD (NRA) (n = 23) and typically developing (TD) controls (n = 23). We found that sAPPtotal and sAPPα levels were significantly higher in children with RA than in children with NRA or in TD controls. In contrast, no difference was observed in sAPPβ levels. In conclusion, increased plasma levels of sAPPtotal and sAPPα may be valuable biomarkers for the early identification of ASD regression. Prospective studies will be conducted using a larger sample to further investigate these differences.

A Multi-Center Study on the Relationship Between Developmental Regression and Disease Severity in Children With Autism Spectrum Disorders

INTRODUCTION

This study aimed to investigate the prevalence of developmental regression in children with Autism Spectrum Disorder (ASD) and to explore its relationship with disease severity.

METHODS

We finally included 1,027 ASD children aged 2-5 years from 13 cities in China: 138 with regressive ASD and 889 with non-regressive ASD. The Social Responsiveness Scale (SRS), Autism Behavior Checklist (ABC), Child Autism Rating Scale (CARS), and Children Neuropsychological and Behavioral Scale-Revision 2016 (CNBS-R2016) were used to evaluate the core symptoms and developmental status of children in the two groups.

RESULTS

Among the 1,027 ASD children eventually included, 138 (13.44%) cases showed regressive behavior and the average regression occurring age was 24.00 (18.00-27.00) months. Among the regressive children, 105 cases (76.09%) had language regression, 79 cases (57.25%) had social regression, and 4 cases (2.90%) had motor regression. The total scores of ABC and the sub-score of sensory and stereotypic behavior (β = 5.122, 95% CI: 0.818, 9.426, P < 0.05; β = 1.104, 95% CI: 0.120, 2.089, P < 0.05; β = 1.388, 95% CI: 0.038, 2.737, P < 0.05), the SRS total scores and the sub-score of autistic mannerisms (β = 4.991, 95% CI: 0.494, 9.487, P < 0.05; β = 1.297, 95% CI: 0.140, 2.453, P < 0.05) of children in the regressive group were all higher than the non-regressive group. The total developmental quotient (DQ) of CNBS-R2016 and the DQ of gross motor, fine motor, adaptive behavior, language (β = -5.827, 95% CI: -11.529, -0.125, P < 0.05) and personal society in the regressive group were lower than the non-regressive group and the proportion of children with intelligent developmental impairment was higher the non-regressive group.

CONCLUSION

Regressive autism is mainly manifested as language and social regression. Children with regressive ASD have more severe core symptoms, lower neurodevelopmental level DQ, and more serious disease degree than children with non-regressive ASD, which requires further etiological examinations and more clinical attention.

Autoimmune Encephalitis and Autism Spectrum Disorder

The concept of "acquired autism" refers to the hypothesis that amongst the massive heterogeneity that encompasses autism spectrum disorder (ASD) there may be several phenotypes that are neither syndromic nor innate. Strong and consistent evidence has linked exposure to various pharmacological and infective agents with an elevated risk of a diagnosis of ASD including maternal valproate use, rubella and herpes encephalitis. Autoimmune encephalitis (AE) describes a group of conditions characterised by the body's immune system mounting an attack on healthy brain cells causing brain inflammation. The resultant cognitive, psychiatric and neurological symptoms that follow AE have also included ASD or autism-like traits and states. We review the current literature on AE and ASD. Drawing also on associated literature on autoimmune psychosis (AP) and preliminary evidence of a psychosis-linked subtype of ASD, we conclude that AE may either act as a potentially causative agent for ASD, and/or produce symptoms that could easily be mistaken for or misdiagnosed as autism. Further studies are required to discern the connection between AE and autism. Where autism is accompanied by regression and atypical onset patterns, it may be prudent to investigate whether a differential diagnosis of AE would be more appropriate.

The relationship between brain abnormalities and autistic psychopathology in pervasive developmental disorders

The aim of the present research has been to determine whether there is a relationship between brain abnormalities found on magnetic resonance imaging (MRI) and autistic psychopathology. A retrospective analysis covering a period between 1998 and 2015 included 489 children with autism (404 boys, 85 girls; average age 8.0 ± 4.2 years) who underwent an MRI of the brain. For clinical diagnosis of autism, the International Classification of Diseases, 10th revision (ICD-10), was used. Autistic psychopathology was evaluated by means of the Autism Diagnostic Interview - Revised. The Spearman nonparametric correlation analysis and chi-square test were used to examine the possible relationships between variables. The group of autistic children did not manifest a statistically significant correlation between the parameters examined on MRI and autistic psychopathology. A correlation between other cysts and repetitive behavior was significant only at trend level (P = 0.054). Gliosis of the brain was significantly more frequent in autistic children with mental retardation than in children without mental retardation (14.1% vs. 7.4%; P = 0.028). Nonmyelinated areas in the brain were significantly more frequent in autistic children with autistic regression than in children without autistic regression (29.9% vs. 15.7%; P = 0.008). Mental retardation was significantly more frequent in autistic children with autistic regression than in children without regression (73.2% vs. 52.5%; P = 0.002). Our research study did not reveal a statistically significant correlation of brain abnormalities on MRI with autistic psychopathology.

Symptom trajectories in the first 18 months and autism risk in a prospective high-risk cohort

BACKGROUND

Although early autism spectrum disorder (ASD) detection strategies tend to focus on differences at a point in time, behavioral symptom trajectories may also be informative.

METHODS

Developmental trajectories of early signs of ASD were examined in younger siblings of children diagnosed with ASD (n = 499) and infants with no family history of ASD (n = 177). Participants were assessed using the Autism Observation Scale for Infants (AOSI) from 6 to 18 months. Diagnostic outcomes were determined at age 3 years blind to previous assessments.

RESULTS

Semiparametric group-based modeling using AOSI scores identified three distinct trajectories: Group 1 ('Low', n = 435, 64.3%) was characterized by a low level and stable evolution of ASD signs, group 2 ('Intermediate', n = 180, 26.6%) had intermediate and stable levels, and group 3 ('Inclining', n = 61, 9.3%) had higher and progressively elevated levels of ASD signs. Among younger siblings, ASD rates at age 3 varied by trajectory of early signs and were highest in the Inclining group, membership in which was highly specific (94.5%) but poorly sensitive (28.5%) to ASD. Children with ASD assigned to the inclining trajectory had more severe symptoms at age 3, but developmental and adaptive functioning did not differ by trajectory membership.

CONCLUSIONS

These prospective data emphasize variable early-onset patterns and the importance of a multipronged approach to early surveillance and screening for ASD.

Neural Correlates of Infant Face Processing and Later Emerging Autism Symptoms in Fragile X Syndrome

Fragile X syndrome (FXS) is the leading known genetic cause of autism spectrum disorder (ASD) with 60-74% of males with FXS meeting diagnostic criteria for ASD. Infants with FXS have demonstrated atypical neural responses during face processing that are unique from both typically developing, low-risk infants and infants at high familial risk for ASD (i.e., infants siblings of children with ASD). In the current study, event-related potential (ERP) responses during face processing measured at 12 months of age were examined in relation to ASD symptoms measured at ~48 months of age in participants with FXS, as well as siblings of children with ASD and low-risk control participants. Results revealed that greater amplitude N290 responses in infancy were associated with more severe ASD symptoms in childhood in FXS and in siblings of children with ASD. This pattern of results was not observed for low-risk control participants. Reduced Nc amplitude was associated with more severe ASD symptoms in participants with FXS but was not observed in the other groups. This is the first study to examine ASD symptoms in childhood in relation to infant ERP responses in FXS. Results indicate that infant ERP responses may be predictive of later symptoms of ASD in FXS and the presence of both common and unique pathways to ASD in etiologically-distinct high-risk groups is supported (i.e., syndromic risk vs. familial risk).

Ethical dimensions of translational developmental neuroscience research in autism

BACKGROUND

Since the 1990s, increasing research has been devoted to the identification of biomarkers for autism to help attain more objective diagnosis; enable early prediction of prognosis; and guide individualized intervention options. Early studies focused on the identification of genetic variants associated with autism, but more recently, research has expanded to investigate neurodevelopmental markers. While ethicists have extensively discussed issues around advances in autism genomics, much less ethical scrutiny has focused on research on early neurodevelopment and on the interventions being developed as a result.

OBJECTIVES

We summarize the current state of the science on the identification of early markers for autism and its potential clinical applications, before providing an overview of the ethical issues arising from increasing understanding of children's neurodevelopment in very early life.

RESULTS

Advances in the understanding of brain and behavioral trajectories preceding later autism diagnosis raise ethical concerns around three themes: (a) New models for understanding autism; (b) Risks and benefits of early identification and intervention; and (c) Communication of early concerns to families. These ethical issues should be further investigated in research conducted in partnership with autistic people and their families.

CONCLUSIONS

This paper highlights the need for ethical scrutiny of early neurodevelopmental research in autism. Scrutiny requires expertise and methods from the basic sciences and bioethics, as well as constructive collaborations among autistic people, their parents, and autism researchers to anticipate early interventions that serve the community's interests and accommodate the varied experiences and preferences of people on the spectrum and their families.

The Toddler Autism Symptom Inventory: Use in diagnostic evaluations of toddlers

LAY ABSTRACT

Determining whether a young child has an autism spectrum disorder requires direct observation of the child and caregiver report of the child's everyday behaviors. There are few interviews for parents that are specifically designed for children under 3 years of age. The Toddler Autism Symptom Inventory is a new interview that asks caregivers of children age 12-36 months about symptoms of possible autism spectrum disorder. The Toddler Autism Symptom Inventory uses a cutoff score to indicate likelihood for autism spectrum disorder; this cutoff score appears to accurately identify most children who are diagnosed with autism spectrum disorder without identifying too many who do not have autism spectrum disorder. The Toddler Autism Symptom Inventory interview can help clinicians to determine whether a young child shows symptoms suggestive of an autism spectrum disorder.

Leveraging telehealth to evaluate infants with prodromal autism spectrum disorder characteristics using the telehealth evaluation of development for infants

LAY ABSTRACT

Many families seeking early evaluations for autism spectrum disorder face long waitlists, must often travel to centers with appropriate expertise, and are frequently told by providers to "wait and see." This results in significant stress for families and delayed supports to infants and their caregivers who could benefit. This study evaluated whether telehealth could be used to identify and evaluate infants with early autism spectrum disorder characteristics in the first year of life. In this study, we evaluated 41 infants via telehealth using a standard set of probes and scored behavior related to social communication, play, imitation, and other developmental domains. We found the majority of infants demonstrated elevated likelihood of autism spectrum disorder on both parent-reported questionnaires and examiner-rated behavior. Caregiver ratings of the overall utility of the protocol used in this study were high. Overall, this study demonstrates the feasibility for telehealth-based approaches to evaluate infants' with elevated likelihood of autism spectrum disorder in the first year of life, which could help to improve families' access to care and to expand our capacity to conduct studies evaluating possible intervention supports.

Age of walking and intellectual ability in autism spectrum disorder and other neurodevelopmental disorders: a population-based study

BACKGROUND

Delayed walking is common in intellectual disability (ID) but may be less common when ID occurs with autism spectrum disorder (ASD). Previous studies examining this were limited by reliance on clinical samples and exclusion of children with severe motor deficits.

OBJECTIVE

To examine in a population-based sample if age of walking is differentially related to intellectual ability in children with ASD versus other neurodevelopmental disorders (NDD).

METHODS

Participants were from the nested Autism Birth Cohort Study of the Norwegian Mother, Father and Child Cohort Study (MoBa). Cox proportional hazards regression assessed if diagnosis (ASD n = 212 vs. NDD n = 354), continuous nonverbal IQ, and their interaction, were associated with continuous age of walking.

RESULTS

The relationship between nonverbal IQ and age of walking was stronger for NDD than for ASD (Group × nonverbal IQ interaction, χ²  = 13.93, p = .0002). This interaction was characterized by a 21% decrease in the likelihood of walking onset at any given time during the observation period per 10-point decrease in nonverbal IQ (hazard ratio = 0.79, 95% CI: 0.78-0.85) in the NDD group compared to 8% (hazard ratio = 0.92, 95% CI: 0.86-0.98) in the ASD group.

CONCLUSIONS

The finding that age of walking is less strongly related to low intellectual ability in children with ASD than in children without other NDDs supports the hypothesis that ID in ASD may result from heterogeneous developmental pathways. Late walking may be a useful stratification variable in etiological research focused on ASD and other NDDs.

Validation of Autism Diagnosis and Clinical Data in the SPARK Cohort

The SPARK cohort was established to facilitate recruitment in studies of large numbers of participants with autism spectrum disorder (ASD). Online registration requires participants to have received a lifetime professional diagnosis by health or school providers although diagnoses are not independently verified. This study was set to examine the validity of self- and caregiver-reported autism diagnoses. Electronic medical records (EMR) of 254 SPARK participants (77.6% male, age 10.7 years) were abstracted. Using two different methods, confirmation of ASD diagnosis in EMRs was obtained in 98.8% of cases. Core clinical features recorded in EMRs were typical of autism samples and showed very good agreement with SPARK cohort data, providing further evidence of the validity of clinical information in the SPARK database.

ESCAP practice guidance for autism: a summary of evidence-based recommendations for diagnosis and treatment

Across Europe, there is increased awareness of the frequency and importance of autism spectrum disorder (ASD), which is now recognised not only as a childhood disorder but as a heterogeneous, neurodevelopmental condition that persists throughout life. Services for individuals with autism and their families vary widely, but in most European countries, provision is limited. In 2018, European Society of Child and Adolescent Psychiatry (ESCAP) identified the need for a Practice Guidance document that would help to improve knowledge and practice, especially for individuals in underserviced areas. The present document, prepared by the ASD Working Party and endorsed by the ESCAP Board on October 3, 2019, summarises current information on autism and focuses on ways of detecting, diagnosing, and treating this condition.

Bayonet-shaped language development in autism with regression: a retrospective study

Background

Language delay is one of the major referral criteria for an autism evaluation. Once an autism spectrum diagnosis is established, the language prognosis is among the main parental concerns. Early language regression (ELR) is observed by 10–50% of parents but its relevance to late language level and socio-communicative ability is uncertain. This study aimed to establish the predictive value of ELR on the progression of language development and socio-communicative outcomes to guide clinicians in addressing parents’ concerns at the time of diagnosis.

Methods

We used socio-communicative, language, and cognitive data of 2,047 autism spectrum participants from the Simons Simplex Collection, aged 4–18 years (mean = 9 years; SD = 3.6). Cox proportional hazard and logistic regression models were used to evaluate the effect of ELR on language milestones and the probability of using complex and flexible language, as defined by the choice of ADOS module at enrollment. Linear models were then used to evaluate the relationship of ELR and non-verbal IQ with socio-communicative and language levels.

Results

ELR is associated with earlier language milestones but delayed attainment of fluent, complex, and flexible language. However, this language outcome can be expected for almost all autistic children without intellectual disability at 18 years of age. It is mostly influenced by non-verbal IQ, not ELR. The language and socio-communicative level of participants with flexible language, as measured by the Vineland and ADOS socio-communicative subscales, was not affected by ELR.

Limitations

This study is based on a relatively coarse measure of ultimate language level and relies on retrospective reporting of early language milestones and ELR. It does not prospectively document the age at which language catches up, the relationship between ELR and other behavioral areas of regression, nor the effects of intervention.

Conclusions

For autistic individuals with ELR and a normal level of non-verbal intelligence, language development follows a “bayonet shape” trajectory: early first words followed by regression, a plateau with limited progress, and then language catch up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00444-8.